Arrangement for sensing the characteristics of a surface and determining the position of points thereon

Abstract

The surface to be sensed or scanned is placed in the path of a projector which is moved along an axis of the surface. The path of motion of the projector is subdivided into predetermined sections which are illuminated by the projector in accordance with a predetermined sequential pattern. This procedure of moving the projector is repeated a predetermined number of times, with a separate illuminating pattern prevailing each time that the projector is moved relative to the surface and traverses the entire surface to be scanned. The combinations of the patterns obtained from the repeated scannings of the projector define closely-spaced sections of the surface. The patterns are coded so that each section is uniquely defined in coded form. A camera having the entire surface within its field of view photographs the surface each time that the projector is moved along the axis of the surface.

We claim: 
     
       1. A method for sensing and locating points on a surface comprising the steps of: generating a projection field directed onto a surface; applying relative motion between said projection field and said surface in at least one direction parallel to a coordinate axis applied to the surface; subdividing said projection field into a number of selected sections during said relative motion and irradiating said surface with different variations of said subdivided projection field so that each section is illuminated at least once; recording within a field of view images of said surface as irradiated by the subdivided projection field; recording a calibrated reference surface and correlating said recorded images in relation to said reference surface to define the location of a predetermined point on said surface first-mentioned and appearing within said field of view. 
     
     
       2. The method as defined in claim 1 including the step of irradiating the selected sections. 
     
     
       3. An arrangement for sensing and locating points on a surface comprising, in combination, means for generating a projection field directed onto a surface; means for applying relative motion between said projection field and said surface in at least one direction parallel to a coordinate axis applied to the surface; said means for applying relative motion between said projection field and said surface subdividing said projection field into a number of selected sections during said relative motion and irradiating said surface with said subdivided projection field; means for recording within a field of view selectively images of said surface as irradiated by the subdivided projection field; a calibrated reference surface; and means for reading said recorded image in relation to said reference surface to define the location of a predetermined point in said sections and appearing within said field of view. 
     
     
       4. The arrangement as defined in claim 3 wherein the selected sections of said surface are irradiated. 
     
     
       5. The arrangement as defined in claim 4 wherein said reference surface is a substantially spherical surface. 
     
     
       6. The arrangement as defined in claim 4 wherein said reference surface has a substantially star-shaped cross-section. 
     
     
       7. The arrangement as defined in claim 2 wherein the recording of said images of said reference surface comprises the recording of substantially points on said reference surface. 
     
     
       8. The method as defined in claim 1 wherein said correlating step comprises further defining the spatial location of said predetermined point on said first-mentioned surface by the intersection of a line and a plane in which said point lies. 
     
     
       9. The arrangement as defined in claim 3 said means for applying relative motion between said projection field and said surface including means for subdividing said sections into a plurality of subsections. 
     
     
       10. The arrangement as defined in claim 4 wherein the spatial location of said predetermined point on said first-mentioned surface is defined by the intersection of a line and a plane in which said point lies. 
     
     
       11. A method for sensing and locating points on a surface comprising the steps of: generating a projection field directed onto a surface; applying relative motion between said projection field and said surface in at least one direction parallel to a coordinate axis applied to the surface; subdividing said projection field into a number of selected sections during said relative motion and irradiating said surface with said subdivided projection field; recording within a field of view selectively images of said surface as irradiated by the subdivided projection field; reading said recorded images to define the location of a predetermined point on said surface and appearing within said field of view, said projection field being subdivided in accordance with a predetermined computational code, said predetermined point being irradiated in accordance with a code assigned to the selection of the projection field irradiating said point; recording selectively images of subdivided sections of a predetermined reference surface; and relating the images of said first-mentioned surface with the images of said reference surface for defining the spatial location of said predetermined point on said first-mentioned surface; the spatial location of said predetermined point on said first-mentioned surface being computed from an intersection of said reference surface with a line from the position of a recorded image of said predetermined point and passing through a lens node used in said recording steps. 
     
     
       12. A method as defined in claim 11, wherein said projection field is subdivided successively in accordance with said predetermined computational code.